Consolidated Statements of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income		$ 59,504	$ 64,540	$ 59,228
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization		5,346	5,515	3,786
Deferred taxes		(2,909)	(1,412)	(246)
Stock-based compensation		944	859	710
Provision for credit losses	[1]	16,047	4,819	6,167
Write-downs of other real estate owned and other repossessed assets		1,454	4,295	2,530
Gains on sale of loans held for sale		(7,226)	(1,880)	(1,288)
Securities (gains) losses		(1,251)	(3)	85
Fair value adjustment in equity securities		(518)	(780)	0
Gain on debt repurchase		0	(219)	0
(Gains) losses on sale of assets, net		390	360	(175)
Proceeds from sale of mortgage loans held for sale		347,048	94,507	56,689
Funding of mortgage loans held for sale		(361,913)	(91,333)	(56,829)
Amortization of securities premiums and discounts, net		5,907	5,042	4,679
Change in cash surrender value of bank owned life insurance		(1,371)	(1,567)	(2,924)
Payment of operating lease liabilities		(1,682)	(1,663)	0
Mortgage servicing rights:
Fair value adjustments		1,064	975	343
New servicing assets created		(1,869)	(631)	(466)
Changes in:
Accrued interest receivable		(982)	(404)	(1,094)
Other assets		1,845	4,941	(14,694)
Accrued interest payable		(1,596)	(63)	(674)
Other liabilities		4,147	(2,440)	9,660
Net cash provided by operating activities		62,379	83,458	65,487
Certificates of deposit in other banks:
Purchase of certificates of deposit		(245)	0	0
Maturity of certificates of deposit		245	3,675	5,880
Securities available-for-sale (AFS):
Purchase of AFS securities		(857,167)	(196,727)	(281,511)
Proceeds from sales of AFS securities		186,194	25,734	153,315
Proceeds from prepayments, calls, and maturities of AFS securities		281,487	174,125	109,701
Securities held-to-maturity (HTM):
Proceeds from prepayments and maturities of HTM securities		517	132	10
Change in loans, net		(306,523)	(46,162)	(93,151)
Purchase of premises and equipment		(1,482)	(2,570)	(2,832)
Proceeds from sale and retirement of premises and equipment		1	48	97
Redemption of stock by Federal Home Loan Bank		426	4,239	3,214
Proceeds from sale of other real estate owned and repossessed assets		4,754	3,641	3,485
Additional investment in bank owned life insurance		(1,733)	(1,241)	0
Proceeds from settlement of bank owned life insurance		0	615	1,202
Net cash used in investing activities		(693,526)	(34,491)	(100,590)
Cash flows from financing activities:
Change in deposits, net		610,510	99,622	42,087
Change in repurchase agreements and federal funds purchased, net		121,539	931	(17,234)
Advances from Federal Home Loan Bank		25,000	30,000	0
Payments on advances from Federal Home Loan Bank		(25,020)	(30,021)	(409)
Payment of finance lease liabilities		(15)	(14)	0
Repurchase of long-term debt		0	(1,281)	0
Issuance of common stock		926	1,264	1,230
Repurchase of stock		(1,099)	0	0
Dividends paid		(27,142)	(26,235)	(24,395)
Net cash provided by (used in) financing activities		704,699	74,266	1,279
Net increase (decrease) in cash and cash equivalents		73,552	123,233	(33,824)
Cash and cash equivalents at beginning of year		264,683	141,450	175,274
Cash and cash equivalents at end of year		338,235	264,683	141,450
Supplemental disclosures:
Income taxes paid		13,275	9,988	9,700
Interest paid		27,047	40,576	28,621
Non-cash activities:
Loans to facilitate the sale of other real estate owned and repossessed assets		9,632	2,879	4,385
Common stock dividends accrued, paid in subsequent quarter		239	221	221
Real estate acquired in settlement of loans		$ 4,446	$ 3,384	$ 5,459

[1] Effective January 1, 2020, the provision for loan losses became the provision for credit losses with the implementation of ASU 2016-13, commonly referred to as CECL.